Iran is ready to revive talks with the West but tougher sanctions will not force it to give in to demands over its nuclear programme, its president says.
On Monday, the EU banned new oil contracts with Iran, saying it was not confident Tehran's nuclear plans were "exclusively peaceful".
President Mahmoud Ahmadinejad said it was evident that "those who resort to coercion are opposed to talks".
Tehran insists its nuclear programme is for energy purposes.
Negotiations between Iran and the five permanent UN Security Council members plus Germany ended in a stalemate in January 2011.
President Ahmadinejad is the highest-ranking Iranian official since then to offer to resume talks.
In a speech made in Kerman, southeastern Iran, and broadcast on state television, he accused the West of trying to ruin negotiations in order to put increased pressure on Iran.
"It is the West that needs Iran and the Iranian nation will not lose from the sanctions," the president said.
"It is you who come up with excuses each time and issue resolutions on the verge of talks so that negotiations collapse,'' he said.
"Why should we shun talks? Why and how should a party that has logic and is right shun talks? It is evident that those who resort to coercion are opposed to talks and always bring pretexts and blame us instead."
BBC correspondent Kasra Naji says Tehran has failed to clarify exactly what kind of talks it is prepared to enter into.
In the last two rounds of meetings, in Turkey and Geneva, Iranian officials were happy to talk about anything except the West's concerns about its nuclear programme, our correspondent added.
EU foreign ministers formally adopted the sanctions against Iran at a meeting in Brussels.
In a joint statement, UK Prime Minister David Cameron, French President Nicolas Sarkozy and German Chancellor Angela Merkel said Iran had "failed to restore international confidence in the exclusively peaceful nature of its nuclear programme".
The EU said the sanctions prohibit the import, purchase and transport of Iranian crude oil and petroleum products as well as related finance and insurance. All existing contracts will have to be phased out by 1 July.
Investment as well as the export of key equipment and technology for Iran's petrochemical sector is also banned.
EU foreign policy chief Catherine Ashton said the purpose of the sanctions was "to put pressure on Iran to come back to the negotiating table".
Iran branded the embargo "unfair" and "doomed to fail", but it was welcomed by US President Barack Obama, who said it showed international unity against the "serious threat" posed by Iran's nuclear programme.
The EU currently buys about 20% of Iran's oil exports.
IAEA Iran visit
Earlier this week, the International Atomic Energy Agency, the UN's nuclear watchdog confirmed it would send a team to Iran between 29 and 31 January "to resolve all outstanding substantive issues".
In a report last November the IAEA said it had information suggesting Iran had carried out tests "relevant to the development of a nuclear explosive device".
Iran sells most of its oil to countries in Asia. The EU and the United States are now working to persuade Asian countries to reduce their purchases from Iran as well.
But Beijing has criticised the European Union for its ban. China - a big importer of Iranian crude oil - has long opposed unilateral sanctions targeting Iran's energy sector. It says the nuclear dispute should be resolved through dialogue.
On Thursday, China's official Xinhua News Agency quoted its foreign ministry as saying: "To blindly pressure and impose sanctions on Iran are not constructive approaches."
Iran has already threatened to retaliate to the sanctions against it by blocking the Strait of Hormuz at the entrance to the Gulf, through which 20% of the world's oil exports pass.
The US has said it will keep the trade route open, raising the possibility of a confrontation.